Clinical behavior of FIGO stage I endometrioid endometrial adenocarcinoma diagnosed as high grade on pre-operative biopsy and low grade on hysterectomy specimen.

OBJECTIVE

Pre-operative endometrial assessment may be discordant with final pathology. We sought to determine the outcome of discordant cases.

METHODS

We identified patients who had primary surgical treatment of stage I endometrioid endometrial carcinoma found on final hysterectomy specimen from January 1, 2000, to December 31, 2020. We collected relevant patient, clinical, and pathologic characteristics and defined low grade as cases with pre-operative grade 1 or 2 tumors and concordant final pathology, and high grade as cases with pre-operative grade 3 tumors and concordant final pathology. We defined discordant as cases with a high-grade histology on pre-operative biopsy, inclusive of non-endometrioid histology, and grade 1 or 2 on final pathology. We compared clinicopathologic characteristics and used Kaplan-Meier survival estimates to compare outcomes between groups.

RESULTS

Overall, 2936 patients were included: 2606 (89%) low grade, 247 (8%) high grade, and 83 (3%) discordant. Five-year progression-free survival was 95.1% for low-grade, 86.9% for discordant, and 86.0% for high-grade tumors (p <.001). Five-year overall survival was 95.0% for low-grade, 93.4% for discordant, and 85.7% for high-grade tumors (p <.001). After adjusting for age, myometrial invasion, lymphovascular space invasion, washings (progression-free survival), performance of nodal dissection (overall survival), and adjuvant therapy, discordant cases were not independently associated with progression-free survival (hazard ratio 1.82, 95% confidence interval 0.71 to 4.65), and only high-grade tumors were independently associated with worse overall survival.

CONCLUSIONS

The clinical behavior of stage I endometrioid endometrial carcinoma diagnosed as high grade on pre-operative biopsy and low grade on subsequent hysterectomy seems to differ from cases diagnosed as low grade on both pre-operative and final pathology. Further analyses and larger series will be needed to better clarify this question. Both pre-operative and final hysterectomy results should be considered along with age, myometrial invasion, and lymphovascular space invasion when counseling patients regarding prognosis and need for adjuvant therapy.